[tex]h = 8cm \\ a = 4cm \\P = 48 {cm}^{2} [/tex]
Wzór
[tex] \frac{(a + b) \times h}{2}[/tex]
Podstawiamy
[tex]48 = \frac{(4 + b) \times 8}{2} | \times 2 \\ 96 = (4 + b) \times 8 \\ 96 = 32 + 8b \\ 64 = 8b | \div 8 \\ b = 8[/tex]
Dłuższa podstawa ma 8cm
